A critical need for disease detection, prognostic prediction, monitoring, and therapeutic decisions is improved assay sensitivity and specificity. At present, biomarkers (proteins, peptides, lipids, RNAs, DNA and modifications thereof for disease-associated molecular alterations) for conditions and diseases, such as cancer, rely almost exclusively on obtaining samples from tissue to identify the condition or disease. Methods to obtain these tissues of interest for analysis are often invasive, costly and pose complication risks for the patient. Furthermore, use of bodily fluids to isolate or detect biomarkers often significantly dilutes a biomarker resulting in readouts that lack requisite sensitivity. Additionally, most biomarkers are produced in low or moderate amounts in normal tissues other than the diseased tissue and thus this lack of specificity can also be problematic.
The identification of specific biomarkers, such as DNA, RNA and proteins can provide bio-signatures that are used for the diagnosis, prognosis, or theranosis of a condition or disease. Exosomes are a good source for assessing one or more biomarkers that are present in or on the surface of an exosome. Furthermore, identifying particular characteristics of an exosome (e.g., size, surface antigens, cell-of-origin) can itself provide a diagnostic, prognostic or theranostic readout.
The secretion of exosomes by cancerous cells, other diseased cells, or at certain times of a physiological process (e.g., pregnancy), can be leveraged to aid in diagnosis as well as individualized treatment decisions. Exosomes have been found in a number of body fluids, including blood plasma, breast milk, bronchoalveolar lavage fluid and urine. Exosomes also take part in the communication between cells, as transport vehicles for proteins, RNAs, DNAs, viruses, and prions.
The present inventions provide an improvement to prior art assays. Products and process are provided for improved assay sensitivity and specificity, allowing for disease detection, prognostic prediction, disease monitoring, disease staging, and therapeutic decision-making, as well as physiological state identification. Products and processes include cell-of-origin specific selection of exosomes and analysis of their protein composition, RNA composition, DNA composition, lipid profile, and relevant metabolic and/or epigenetic modifications of these analytes. Also provided herein are methods of determining biomarkers and bio-signatures for exosomes without prior concentration or purification of the exosomes from a sample.